Two temperature refrigerator



June 20, 1950 s. K. IWASHITA 2,511.351

no mm REFRIGERATOR Filed July 14, 1943 v 4 Sheets-Shoat 1 1 l inn 4 Sheets-Sheet 2 June 20, 1950 e. K. IWASHITA 2,511,351

'rwo TEMPERATURE REFRIGERATOR Filed July 14. 1943 4 Sheets-Sheet 3 h" we? r.

June 20, 1950 a. K. IWASHITA 2,511,351

no mum-ms REFRIGERATOR Filed July 14. 1943 4 Shoots-Sheet 4 Patented June 20, 1950 TWO TEMPERATURE REFRIGERATOR George K. Iwashita, indlanapolk,

Ind asslgnor,

by mesne assignments, to Admiral Corporation. Chicago, IIL, a annotation of Delaware Application July 14, 194:, Serial No. 494,629

12 Claims. (01. 82-05) This invention relates to refrigerators and particularly to refrigerators of the type having two compartments or portions maintained at different temperatures.

An object of the invention is to provide an improved two-temperature tor.

Another object of the invention is to provide an improved refrigerator of the type having primary and secondary refrigerant circuits.

Another object of the invention is to provide an improved two-temperature refrigerator having primary and secondary refrigerant circuits.

Yet another object of the invention is to provide a refrigerator of the type having primary and secondary refrigerant circuits, wherein circulation of the refrigerant in the secondary circuit is maintained without employing pumps or the like as a means for forcing the refrigerant through the circuit.

Yet another object of the invention is to provide an improved refrigerator having a complete refrigerating system including compressor, condenser, and evaporator, which is conveniently removable as a unit from the refrigerator cabinet for servicing.

Other objects and advantages of the invention will become apparent during the description, reference being had to the accompanying drawings, wherein:

Fig. i is a front view of a refrigerator of the two-temperature type;

Fig. 2 is a vertical section showing the interior arrangement of the refrigerator of Fig. 1:

Fig. 3 is a section taken through a refrigerator having a modified arrangement;

Figs. 4 and 5 illustrate further modifications of the invention;

Fig. 6 is a close-up illustrating certain details of the modification shown in Pig. 5; and

Figs. 7, 8 and 9 illustrate still further embodiments of the invention.

As illustrated in Figs. 1 and 2, the refrigerator comprises a cabinet l2. liners II and it supported therein by means of breaker strips l8 and insulated from the cabinet by means of insulation 20, a machinery compartment 22 housing a compressor and condenser, and a door normally sealing the interior of the liners II and It, having an outer shell 24 and metal panels 28 and it insulated therefrom and arranged to close the front ends of the liners I4 and II, respectively. A rubber gasket 30 seals the interior of the liners when the door is closed. The upper liner It forms a food storage compartment which is maintained at 2 point, while the lower liner It forms a freezing compartment. sometimes referred to as a frost chest.

A primary refrigerating system associated with the refrigerator includes the sealed motor-compressor unit 3! and the condenser 34 positioned in compartment 22. In addition, the primary system or circuit includes upper and lower coils 38 and II which constitute heat absorbing evaporators. The outlet of condenser 84 is connected by means of a capillary tube 40 to the upper coil 3|. A conduit 42 having a pressure reduction valve 4 connected therein leads from the outlet of coil 8. to the inlet of coil 38. Conduits l8 and 48 connect the inlet and outlet. respectively, of the compressor to coil 3! and condenser 34.

The upper evaporator coil It is mounted on a thin heat conducting metal plate III in the upper portion of the refrigerator cabinet. and the lower evaporator coil It is likewise mounted on a thin heat conducting metal plate I2. As illustrated, both coils It and 88 are serpentine in form and lie flat against the respective plates.

A closed secondary circuit containing a vola-' tile liquid refrigerant is associated with the upper liner I4, and comprises an evaporator portion ll wrapped around the top. sides and back of liner l4, and a condenser portion I! which is a coil mounted on a thin heat conducting metal plate 58. The plate if is secured by suitable means to plate 5. on which the evaporator coil of the primary circuit is mounted. A downwardly extending conduit it connects the low side of condenser portion IQ of the secondary system with the low side of the evaporator portion I. Another connecting conduit 62 slants upwardly from the upper end of the evaporator portion It to the top of the vertical condenser coil It.

Another secondary circuit is amociated with the lower liner it. This circuit comprises a condenser portion," mounted on a flat heat conducting metal plate I, an evaporator portion OI wrapped around the top and bottom, sides and rear of liner II, a conduit ll connecting the condenser portion 84 with the low side of the evaporator portion BI, and an upwardly slanting conduit 12 connecting the upper side of the evaporator portion with the condenser coil Ill. The plate II is secured by suitable means to the plate 52.

In operation of the refrigerator. refrigerant vapor compressed by the compressor I2 is first circulated to condenser 34 where it is cooled and liquefied. Subsequently it passes through capila cool temperature, but preferably above the dew u lary tube it, wherein it is prevented from ex- 3 panding'byflierestrlctingeilectofthetube, to evaporator It, wherein it begins expansion. 'Iheofpartoftheliquldtothegaseous state in evaporator a absorbs heat through thcheattransfu'platesflandllfromthecondemercoilltoftheuppersecondarycircuit. The

rcfrigerantofthiscircuitwhlchis vaporized. Finally, the refrigerant in the circuit rises through conduit '2 to condenser coil it whence it is again liquefied to return to the evaporator portion.

The refrigerant in the primary system, leaving their condensers in order that the circulation evaporator I! in a partially expanded state,

passes thrown the pressure reduction valve M which maintains a pressure diflerential between the two primary mtem evaporators II and il, in order to maintain a predetermined temperature diilerent'ial between the upper and lower liners of the refrigerator. The refrigerant is permittedtoexpandfullyin theevaporator coil SI and its evaporation absorbs large amounts of heat through the heat transfer plates it and 52 from the condenser coil u ofthe lower secondary circuit. The refrigerant in the lower secondary circuit is thus liquefied in condenser portion GI and is then carried by conduit I. to the low side of the evaporator portion 68, where it evaporates. withdrawing heat from liner l8 and the interior thereof, and gradually upward through the coil toward conduit 12 and the condenser where the cycle begins again. The vaporized refrigerant in the primary system is drawn into the intake side of comr 32 through conduit ,andisihentobeginthe primary cycle.

In general, the lower compartment is maintained at a low temperature and a low relative humidity, whereas the upper compartment is maintained at a higher temperature and a higher humidity to serve a somewhat diiferent purpose in the storage of foods.

It will be apparent that the refrigerator arrangement described provides secondary means for cooling the compartments of the refrigerator wherein the flow of the refrigerant is obtained without the need of pumps or the like to force circulation, and the primary circuit is so arranged as to be readily removed from the cabinet for repair or replacement. It will be noted that the primary evaporator coils IO and II are not particularly deeply imbedded in the insulation 20. The refrigerator is provided with a removable rear panel II to permit removal of the primary evaporator coils I8 and il. In removing, the plates II and I! are loosened from the plates II and It, respectively, the compressor 82 is loosened from its support, and the entire primary system is taken out. Repair of the system may then be accomplished in a central service station having the n 1 facilities. By positioning the condenser coils of the secondary circuits vertically as shown, the necessity for a trap to prevent draining of the condensate back through the evaporator portion is avoided. In both instances the evaporator portions of the secondary systems are substantially wholly below inthesecondarysystemswillbesatlsfactorily maintained. The secondary system evaporators. which are wrapped around the respective liners and are therefore deeply imbedded in the insulation, will not need to be removed from the refrigerator at any time.

In the modified embodiment of the invention shown in Fig. 3, the primary refrmerant circulating circuit has a single evaporator coil II which is in heat transfer relationship with the condensers of two secondary circuits. The, outlet side of the primary system is connected by means of a capillary tube ll to the inlet of evaporator coil 88, and the evaporator outlet coil 92 is connected to the inlet of the primary system compressor. One of the two secondary circuit comprises an evaporator coil 84 in heat transfer relationship with the lower liner it, and the condenser II in heat exchange relationship with the evaporator coil of the primary system and mounted between metal plates 98 and Hill which confine both the condenser coil of the secondary system and the evaporator coil of the primary system. The other secondary system comprises an evaporator portion liil in heat transfer relationship with the liner it, and a condenser portion Ill in heat transfer relation with the evaporator portion 88 of the primary system by means of a metal plate lot on which the condenser I is mounted, and by means of suitable spacer elements iill which are confined between plates it and as. Because the condenser 96 of the secondary system which cools liner i5 is in direct heat exchange relation with the evaporator 01 the primary system. whereas the condenser ill of the secondary system which cools the liner II is in heat exchange relation with the primary evaporator through the spacers iilii, the desired temperature diiferential between compartments I4 and it may be maintained by choosing spacers "ll of the proper type and size to maintain the heat exchange rate of compartment it above the heat exchange rate of compartment ll, according to the desired ratio.

This arrangement simplifies the primary system, since it requires a single primary evaporator. It has the same advantages, that the primary system is easily removable for servicing and that the secondary system is so arranged as to have a constant circulation of refrigerant according to the principles of fluid flow. Furthermore, the need for a pressure return valve like the valve 44 of Fig. 2 is avoided by using the spacers iilil to maintain the proper diiferential in temperature between the upper and lower compartments.

In the refrigerator shown in Fig. 4, the compartments are inverted, with the freezing compartment II in the upper portion of the refrigerator and the higher temperature higher numidity compartment It in the lower part of the refrigerator cabinet. The restricted tube on which leads from the condenser of the primary system is connected to the lower primary evaporator III, which is in heat transfer relation with the condenser III of a system having an evaporator Ill in heat exchange relation with the liner H, the primary evaporator ill and the secondary condenser H2 being confined between plates lit and III, the inner plate of which is spaced from the wall of the liner II. A short length of capillary tube II. which prevents complete expansion of the refrigerant in the lower primary evaporator coil connects the outlet of said coil to the inlet of the upper primary evaporator with the liner wall and with the condenser Ill of a secondary circuit which includes an evaporator portion ill in heat exchange relation with the sides, rear and bottom of liner Ii. The effect of capillary tube llll-and the spacing of the evaporator coil Ill from liner ll cooperate to maintain a temperature differential between the compartments I4 and ii.

In the refrigerator of Figs. 5 and 8. the primary circuit has a. single evaporator coil I32 in direct heat exchange relation with the liner or frost chest It. The coils of the evaporator II! are secured to the walls of liner It by means of metallic Permagum I. The liner It is supported at the rear by a nonheat conducting block I, and

is removably held in position by means of a tensioned strapping III which can be disconnected at "0 to permit removal of the liner. The condenser coil "2 of a secondary circuit having an evaporator coil I in heat exchahge relation with liner II is removably mounted on the side of the liner It by means of a bracket 6.. The condenser III of the secondary system is therefore in heat exchange relation with the walls of liner I6 and through them with the evaporator III of the primary system. Th primary evaporator thus directly cools the frost chest l6 and at the same time cools the refrigerant in the secondary system in order that said secondary system may withdraw heat from liner II. In order that the cooling of liner ll may be improved, the space between the lower wall of liner II and the upper wall of liner I4 is left uninsulai'ed, allowing transfer of heat from the lower liner to the upper liner by convection. The removable panel ill. provided in the rear of the refrigerator cabinet for removing the frost chest and the primary evaporator is relatively small, and the restricted tube 80 and return conduit 92 are outside the refrigerator body for the greater part of their length. As in the other embodiments of the invention. the primary system is removable for servicing and the slope of the secondary coils is such that the proper flow of refrigerant is obtained. The primary refrigerating system may be removed from the cabinet by removing the panel I48, with drawing the insulation between the back of the liner i8 and the panel I", opening the connection at I", and releasing the bracket H6. The coils of the secondary system are spread outwardly slightly to permit the low temperature compartment liner and the evaporator coils. which are secured thereto. to be withdrawn through the opening which is normally closed by the panel 8.

In the modification shown in Fig. 'l, the primary system is provided with two evaporator-s, including an upper evaporator I50 which is in heat exchange relation with the condenser I52 of a secondary system, which has an evaporator portion ill in heat exchange relation with the higher temperature compartment ll. The other evaporator coil iii of the primary system is in direct heat exchange relation with the low temperature liner ii, the evaporator being coiled around the top, bottom, sides and rear of said liner. with this arrangement no dual pressure control valve is required inasmuch as the pressure differential between liners I4 and I I may be obtained through the direct contact of primary evaporator coil I" with liner it as against the provision of a secondary system intermediate the primary evaporator ill and the liner II. The coils of the lower primary evaporator ll! are not fixedly secured to liner ll, but instead are so arranged that the primary system may be removed for servicing without disturbing said liner.

In the refrigerator of Fig. 8, the primary system is provided with two evaporators. The upper evaporator IN is in direct heat exchange relation with the frost chest I, and the lower evaporator llll is in heat exchange relation with a metal container It! which is filled with a utectic brine I. The evaporator I maintains the brine at a low temperature and the brine in turn cools the walls of liner ll.

In the refrigerator of Fig. 9, the primary circuit is again provided with an upper evaporator m in direct heat exchange relation with the frost chest ll and a second evaporator portion I. In this case. the heat exchange between the liner I4 and evaporator I is accomplished by circulation of air around the liner ll, there being no insulation around the surface of liner ll. In order to improve air circulation a fan I" driven by an electric motor IIII may be used to blow air across the coils of the primary evaporator. The need for a secondary circuit is thus eliminated entirely.

Although several embodiments of my invention have been described. it will be apparent to those skilled in the art that numerous other modifications might be derived without departing from the fundamental principles of the invention. It is, therefore, my intention that the terms of the following claims should constitute the only limitation in scope of the invention disclosed.

I claim:

I. In a refrigerator having a lower low temperature compartment and an upper higher temperature compartment, a secondary refrigerant circulating system having an evaporator portion in heat exchange relation with the upper compartment and having a condenser P rtion above said evaporator portion, a separate secondary refrigerant circulating system having an evaporator portion in heat exchange relation with the lower compartment and having a condenser portion above the associated evaporator portion, and a closed primary refrigerating system having an upper evaporator in heat exchange relation with the condenser of the first secondary system and a lower evaporator in heat exchange relation with the condenser of the second secondary systom.

2. In a refrigerator having two compartments maintained at different temperatures, a secondary refrigerant circulating system having an evaporator portion in heat exchange relation with one of said compartments and having a condenser portion, a separate secondary refrigerant circulating system having an evaporator portion in heat exchange relation with the other compartment and having a condenser portion, and a closed primary refrigerating system having an evaporator constructed and arranged for ready removability and maintained in heat exchange relation with the condenser of one of the secondary systems and a second evaporator constructed and arranged for ready removability and maintained in heat exchange relation with the condenser of the other secondary system.

3. In a refrigerator having two compartments maintained at different temperatures, a secondary refrigerant circulating system in heat transfer relation with one of said compartments, another secondary refrigerant circulating system in 7 heat transfer relation with the other compartment, and a closed primary refrigerating system including an evaporator portion having a coil removably maintained in heat transfer relation with one of the secondary systems, a second coil removably maintained in heat transfer relation with the other secondary system, means connecting the coils of the evaporator, and a pressure reduction control valve in said connecting means, whereby a higher pressure may be maintained in one of the evaporator coils than in the other.

4. In a refrigerator having two compartments maintained at different temperatures, a secondary refrigerant circulating system in heat transfer relation with one of said compartments, another secondary refrigerant circulating system in heat transfer relation with the other compartment. and a closed primary refrigerating system including an evaporator portion having a coil removably maintained in heat transfer relation with one of the secondary systems. a second coil removably maintained in heat transfer relation with the other secondary system, and means connecting the coils of the evaporator, said connecting means having means whereby a higher pressure may be maintained in one of said coils than in the other.

5. A refrigerator comprising a liner forming a relatively sh temperature, high humidity compartment, a secondary refrigerating system having a part in heat transfer relation with said liner, a second liner forming a low temperature compartment, and a sealed primary refrigerating system including an evaporator portion having a part thereof removably maintained in heat transfer relation with a condenser part of the secondary refrigerating system, and another part thereof connected in series of the first part and removably maintained in heat transfer relation with the low temperature compartment linear.

8. In a refrigerator having a lower low temperature compartment and an upper higher temperature compartment, a secondary refrigerant circulating system having a heat absorbing portion in heat exchange relation with the upper compartment, and a primary refrigerating system having a heat absorbing section, a portion of which is in heat exchange relation with the secondary circuit at a point above the heat absorbing portion of said secondary circuit. and a portion of which is in heat extracting relation with the lower compartment, said portions of the primary heat absorbing section being connected in series.

7. In a refrigerator having a lower low temperature compartment and an upper higher temperature compartment, a secondary refrigerant circulating system having a heat absorbing portion in heat exchange relation with the upper compartment, and a primary refrigerating system having a heat absorbing section, a portion of which is in heat exchange relation with the secondary circuit at a point above the heat absorbing portion of said secondary circuit, and a portion of which is in heat extracting relation with the lower compartment. said portions of the primary heat absorbing section being connested in series, and means for causing the circulation of refrigerant in the primary circuit.

8. A refrigerator comprising a liner forming a low temperature compartment, a liner forming a higher temperature compartment, a secondary refrigerating circuit in heat transfer relation with the higher temperature compartment liner, and a closed primary refrigerating system including an evaporator having a coil removably maintained ,throushthesecondaryrefrigeratingcircmtserving to maintain a temperature differential between the two compartments.

9. Arefrigerator a liner which forms a low temperature compartment, a second liner spaced from theilrstlinerwhichfcrmsaliigher temperature compartment, means thermally insulatingsaidlinersfromeachothenasecondary refrigerant circulating system having a heat absorbing portion in heat exchange relation with the higher temperature cot liner and having a condenser portion, a prhnary refrigerant circulating system having an evaporator coil. said primary evaporator coil having a portion in heat absorbing relation with the low temperature compartment liner and another portion in heat absorbing relation with the condenser portion of the secondary system, and a thermally conductive member positioned between and in heat exchange relation with said condenserandsaidsecond mentionedportionofsaidprimary evaporator coil.

10. A refrigerator comprising a liner which forms a low temperature compartment, a second liner spaced from the first liner which forms a higher temperature compartment, a refrigerant circulating system having a heat absorbing portion in heat exchange relation with the higher temperature compartment liner and havingacondenserportiomaprhnaryrefrigerant circulating systemhavinganevaporatorcoil, said evaporator coil having a portion in heat absorbing relation with the low temperature compartmentlinerandanotherporfloninheatabsorbing relation with the condenser portion of the secondarysystemandaheatexchangecontact plate in heat exchange contact with the primary evaporator and the to facilitate the heat transfer therebetween.

11. A mum-temperature, multi-compartment refrigerator comprising a first liner forming a food storage compartment, a second liner separatedand spacedfromsaidilrstlinerandformingasecondstorageentandarefrigerating means for extracting heat from said compartments and maintaining a temperature differential between said ts, said means comprising a secondary refrigerating system having an evaporator portion in heat transferrelation with said first lines and having a condenser portion above said evaporator portion, and a sealed primaryrefrlgerating system including an evaporator portion, mid evaporator portion having apartarranged-indirect heat exchangerelationwithsahiseeondlineranda second part removably maintained in heat exchange relation with said secondary system candenser portion, said portion and said second part of said primary evaporator being of convoluted form and being arranged in parallel planes, and a refrigerant liquefying means connected to said primary evaporator portion, said primary refrigerating system being of sufficient capacity for M the heat dissipated by said condeme portion and by said second liner.

12. A multi-temperature, multit 9 refrigerator comprising a first liner forming a food storage compartment, a second line: separated and spaced from said first liner and formins a second storage compartment, means thermally insulating said liners from each other, and a refrigerating means for extracting heat from said compartments and maintaining a temperature differential between said compartments, said refrigerating means comprising a secondary rcfrigerating system having an evaporator portion 10 Number in heat transfer relation with said first liner and having a generally flat coiled condenser portion above said evaporator portion, and a sealed primary refrigerating system including an evaporator portion, said evaporator portion having a first part arranged in direct heat exchange relation with said second line:- and a second part removably maintained in heat exchange relation with said secondary system condenser portion, said second part of said primary evaporator portion having a generally fiat coiled form, and a refrigerant liquei'ying means connected to said primary evaporator portion, said primary refrigerating system being of suflicient capacity for extracting the 10 heat dissipated by said secondary condenser portion and by said second liner.

GEORGE K. IWABHITA.

REFERENCE CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date 1,798,951 Munters Mar. 31, 1931 1,565,513 Gaugler July 5, 1932 1,926,384 Hall Sept. 12, 1933 2,035,573 Smith Mar. 31, 1936 15 2,101,656 Steenstrup Dec. 7, 1937 2,309,797 Stickel Feb. 2, 1943 2,405,392 Atchison Aug. 6, 194d 2,416,354 Shoemaker Feb. 25,194! 2,416,777 Schweller Mar. 4, 1947 20 FOREIGN PATENTS Number Country Date Germany Apr. 28, 1983 

